Conveyor belts are commonly found in various industrial facilities and move objects of various shapes and weights along predetermined transport paths. In cases where objects are prone to rolling (e.g., grinding balls supplied to a grinding ball mill(s) via a conveyor), the transport path is typically horizontal.
While such configurations are conceptually very simple, various problems may arise in practice, particularly where the objects are prone to movement. For example, where grinding balls are discharged from a conveyor or storage unit through a chute onto a lower second conveyor that includes a weighing scale (typically located under the conveyor to monitor the weight of balls supplied to the grinding ball mill per unit time), the grinding balls often keep rolling on the second conveyor, causing the scale to malfunction or to provide inaccurate measurement. Where objects do not have a tendency to move or roll, an intermediate conveyor with adjustable belt velocity can be implemented such as to control vertical and horizontal speed of packets or mail items as described in U.S. Pat. No. 6,874,615. This and all other extrinsic materials discussed herein are incorporated by reference in their entirety. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply. Unfortunately, intermediate conveyors are generally not effective for objects that have tendency to move or roll.
Other known mechanisms to overcome difficulties associated with variable feed rates of material that is fed to a conveyor belt with weighing mechanisms are described in GB 0 738 785 and GB 1 569 918. However, while such mechanisms often help overcome uneven distribution of certain materials on a conveyor belt, they once more fail to solve difficulties associated with materials that have a tendency to roll on the belt onto which they have been deposited.
Thus, there is still a need for improved material flow control in conveyor belt systems, especially where materials are prone to movement or rolling upon delivery from a delivery chute or conveyor belt having a vertical offset.